K-Series USB problem resolved and question?

[bbhrrr]

Hi All

My first post.

I had my K-Series controller not being recognized when plugged into USB.
After a home studio move I realised the USB cable I was using was not the one I had started with, this one was much longer and was not working.
I then found the original one which worked with no problems.

(I gather this might be a voltage issue when the cable is too long)

My question is What is the maximum length of USB cable I can use?

Any help would be appreciated, Cheers.